Preparation of 1-benzoyloxydipropyl sulfide



United States Patent 3,290,356 PREPARATHUN 0F l-BENZUYLQXYDIPROPYLSULFEDE George Sosnovsky, Chicago, ili., assignor to IIT ResearchInstitute, a corporation of Illinois N 0 Drawing. (Jontinuation ofapplication Ser. No. 88,627, Feb. 13,, 1961, now Patent No. 3,144,438,dated Aug. II, 1964. This application Mar. 19, 1963, Ser.

1 Claim. (Cl. 260-476) This application is a continuation of myco-pending application of the same title, Serial No. 88,627, filedFebruary 13, 1961, now US. Patent 3,144,438.

The present invention relates generally to the reaction of selectedthioethers with peresters and to a number of novel organic compoundsresulting from such process. More specifically my invention is directedto the reaction of tertiary butyl peresters with aliphatic and cyclicsulfides, to yield among others, alpha-acyloxy sulfide derivatives.

By stopping the present reaction at various intermediate stages thereof,I have been able to produce a number of compositions which include thoseof the general category comprising acyloxy compounds, particularlya-acyloxy sulfide derivatives, alcohols, unsaturated thioethers andorganic acids, all of which may be recovered by the practice of myprocess.

Another important aspect of my invention is the utilization of a coppersalt catalyst in carrying out these processess.

The compounds resulting from the present processes are useful in anumber of ways. They can be intermediates in the synthesis ofbiologically active chemicals, antioxidants, and additives inpolymerization formulations. Of even more obvious interest is theimportant fact that the introduction of the acyloxy group into thesulfide mole cule eliminates the well known objectionable odor commonlyassociated with sulfides.

The most pertinent prior art of which I am aware teaches that organicsulfides are oxidized by peroxides to sulfoxides and suslfones. Numerouspreparative methods, for example, those which employ hydrogen peroxideor eracetic or perbenzoic acids, are available to the chemist active inthis field. In addition to this it has been shown that organicperoxides, such as cyclohexanyl and t-butyl hydroperoxides, likewiseoxidize various sulfides to sulfoxides.

In contradistinction to such teachings of the prior art I have nowdiscovered that t-butyl peresters smoothly react in the presence ofcopper salt catalysts with both cyclic and acylic aliphatic sulfides,such as tetrahydrothiophene and n-propyl sulfide, to give good yields oftheir respective wacyloxy derivatives. For example, the reaction oft-butyl erbenzoate with tetrahydrothiophene proceeds as follows:

Likewise t-butyl peracetate reacts with n-propyl sulfide:

"ice

These and other objects, features and advantages of my 7 invention Willbecome apparent to those skilled in this particular art from thefollowing detailed disclosure thereof.

Commencing with one of the most simple embodiments hereof, I havediscovered that compounds such as diethylsulfide readily react in thepresence of copper ion, particularly cuprous, with t-butyl peresters, e.g., peracetate, to yield a-acyloxy compounds. Thus:

In its most general terms this aspect of my invention, namely thepreparation of a-acyloxy sulfide derivatives is seen from the followingreaction:

wherein R R and R comprise alkyl or aryl groups or the like and may bethe same or different.

In such reaction it is noted that the perester splits between its oxygenbonds while at the same time one alpha hydrogen atom splits oif thesulfide. Such hydrogen comblues with the C(CH O to form t-butyl alcoholwhereas the acyloxy radical,

o R C adds to the oz-CEIIbOIl atom vacated by such hydrogen. Thisconcludes the first step of my reaction.

While I am not completely certain of the theoretical considerations orchemical mechanisms which underlie the broadest aspects of my process,apparently such is a twostep affair generally speaking as follows:

On Thioether Perester Aeyloxy Alcohol II Acyloxy Unsaturated ThioetherAcid eat;

3 One of the important aspects of my invention involves the reaction oftetrahydrothiophene with t-butyl peresters to first form a-acyloxyderivatives and then the unsaturated compound, 2,3 dihydrothiophene.Thus:

(2,8-dihydrothiopl1ene) When t-butyl peracetate is employed thefollowing reaction-s occur:

' 1 +on 0 on 3 \O Instead of employing the cyclic sulfide compounds, asnoted above the present process is likewise useful with straight chainaliphatic sulfides. Thus:

II On CH3CHzCH2SCHz-CH; OH COOC(C s)3 C (CH3)3OH CH3OH2CHSCH2OH3 OfiCH lheat My invention may be further understood by reference to thefollowing specific examples:

Example I To a mixture of tetrahydrothiophene (44 g., 0.5 mole) andcuprous bromide (0.1 g., 0.35 millimole) there was added t-butylperbenzoate ('50 g., 0.25 mole) over a fourhour period while thereaction mixture was maintained at .a temperature of between 95 and 105C. Following this the reaction mixture was cooled to room temperature,50 ml ether was added and such solution was then washed with 2 N sodiumcarbonate to remove benzoic acid (9.7 g. 25% yield). The mmainingethereal solution was then Washed with water, dried with sodium sulfateand concentrated on a steam bath. 1 then distill d the remaining oil atreduced pressure to obtain the following:

(A) Tetrahydrothiophene g.

5 (l3) 2-benzoxytetrahydrothiophene, 36 g.

As to compound B it is noted that this represents a yield of 70%. Thecompound was characterized by a 71 of 0.5662 and could not be furtherdistilled without decomposition. Purification for subsequent analysiswas then After the usual workup of cooling, washing, drying,concentration, etc. as set out above, the remaining oil was distilled.The major products of such distillation were Grams Tetrahydrothiophenel0 Residue 2 2acetoxytetrahydrothiophene 25 (56%) The latter suchcompound is characterized as follows:

Analytical Calculation for C HmO2S Found 49.53 7.16 141 151. (0.1 nnn.)(MT-62 C. nu 1.4803

It may be interesting to note that without the cuprous bromide and afterten hours of reaction time, the same reactants gave only a 38% yield of2-acetoxytetrahydrothiophene.

Example III Tertiary butyl perbenzoate (40 g., 0.2 mole) was added overa five-hour period to a mixture of n-propyl sulfide (48 g., 0.4 mole),benzene (50 ml.) and cuprous bromide (0.35 mole) at 85-90 C. Aftercooling the reaction mixture was Washed with 2 N sodium carbonatesolution to remove benzoic acid, 6 g. (25%). The oil remaining wasdistilled at reduced pressure to yield the following:

Grams n-Propyl sulfide 12 l-benzoyloxy dipropyl sulfide (69% yield) 33The latter such compound is characterized as follows:

Analytical Calculation for C 311180 3 Found C 65.53 65.59 H 7. 61 7. 73S 13. 47 13.74 Mol. Wt 23s 231 B1. (0.4 mm)"- 88-90 C 71,.. 1.5175

Under similar experimental conditions, but without catalyst, 41% bnezoicacid and 52% of l-benzoyloxy dipropyl sulfide were obtained.

Example IV It will be understood that various modifications andvariations may be effected without departing from the spirit or scope ofthe novel concepts of my invention.

I claim as my invention:

5 The method of making l-benzoyloxydipropyl sulfide which comprises thesteps of:

mixing n-propyl sulfide with tertiary butyl perbenzoate in the presenceof cuprous bromide at a temperature of from 8590 C., and separating saidl-benzoyloxydipropyl sulfide from the 2-benzoyloxytetrahydrothiophene (7g., 0.035 mole) was heated to 110 to 140 C. for two hours in a partialvacuum (10 mm. Hg) in apparatus provided with a trap.2,3-dihydrothiophene, 2.4 grams, representing a yield of 83% wascondensed in such trap as cooled by a Dry Ice isopropanol mixture. Suchproduct was then distilled to a constant refractive index, noted below.Gas chromatography showed one large peak; less than 1% impurities 10were present other reaction products.

Analytical Calculation tor C4H -S Found References Cited by the ExaminerC 55 76 55 41 UNITED STATES PATENTS 15 gfwfil: g 5- 2,617,778 11/1952Gluesenkamp 260-476 BI. (100 111111.). 48 C. 1-5268 R. K. JACKSON,Primary Examiner.

The pot residue provided a quantitative yield of benzoic LORRAINEWEINBERGER Examinell' acid. 20 T. L. GALLOWAY, Assistant Examiner.

